JPH0765922B2 - Electronic balance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an electronic balance. The present invention is applicable to so-called electronic balances such as electromagnetic force balance type, so-called electronic balances such as load cell type using tuning strain gauges, tuning fork type, or capacitance type, and electrical weight measuring devices based on other types. It is also applicable to.

<Prior art and its problems> In an electronic balance, especially a high-precision electronic balance, it is difficult to completely compensate the temperature in a non-equilibrium state of temperature, and an accurate measured value is obtained in such a state. It is not possible. Therefore, generally, warming up for about 30 minutes to 3 hours after energization is required.

By the way, the person who uses the electronic balance does not always turn on the power when using the electronic balance. If the power is already on, does the warm-up process finish? It is impossible to determine whether or not the power has just been turned on. Therefore, even if the warm-up is insufficient, you may get an incorrect measurement value by using it, or
In order to obtain an accurate measurement value, there is a problem that a further useless time is spent even though the warming up is actually completed.

Here, the above problem seems to be solved by providing a timer for measuring the elapsed time after energization and notifying the completion of warming up after a predetermined time has elapsed after energization. In the case of simply measuring the elapsed time after energization, for example, when the energization is temporarily stopped in the warming-up completed state and then energized again in a short time, etc., although the warming-up is actually completed, There is a problem in that correct notification cannot be performed, such as notification of insufficient warm-up until a long time has passed.

An object of the present invention is to provide an electronic balance capable of always accurately informing whether or not the balance is in a warm-up completion state.

<Means for Solving Problems> In order to achieve the above-mentioned object, in the first invention, a position near an electrical component that causes a large temperature rise due to self-heating due to energization of the balance, and the electrical component thereof. The temperature sensors are arranged at least at two positions, that is, at a position away from the position where the temperature rise due to energization is small, and the output from each temperature sensor is taken in, and the difference is within a preset difference. It is characterized by the provision of discrimination means for deciding that warming-up is insufficient at one time and warming-up completion when exceeding the difference, and display means for displaying the discrimination result.

Further, in order to achieve the same object, in the second invention, a first time measuring means for measuring an elapsed time after energizing the balance,
Second time measuring means for measuring the duration of the power-off state,
It is provided with a judging means for judging whether or not the warming-up is completed depending on whether the measurement result by the first time measuring means is a preset time or more, and a display means for displaying the judgment result. , The output of each timing means is taken in, the elapsed time after energization is corrected by the subsequent energization stop time, and the elapsed time after correction is set as the initial value of the first timing means when reenergized after the energization stop. It is characterized by having a correction means for setting.

<Operation> In an electronic balance, generally, when electricity is started from a state in which the temperature of each part inside the balance has not been energized for a long time and shows a substantially uniform distribution, a transformer or the like that self-heats by energization is used. The temperature in the vicinity of the electrical parts rises to some extent rapidly with the passage of time, but the temperature at positions far from it does not show a sharp rise, and the temperature difference between the two gradually increases with the passage of time after the start of energization. To go. Then, when the temperature difference between the two reaches a certain temperature, the temperature equilibrium state of the balance is obtained, and it becomes possible to perform temperature compensation correctly thereafter.

The first aspect of the present invention directly measures such a phenomenon to notify the completion / insufficiency of warming up. A temperature sensor is provided at each of the two locations having different temperature rise rates as described above. When the temperature measurement result of each temperature sensor exceeds a certain temperature difference, by displaying the completion of warming up, it is possible to always display the correct display regardless of the length of the power-off time before reaching the power-on state. I have to.

On the other hand, according to the second aspect of the invention, the energization time required to reach the temperature equilibrium state as described above is the energization stoppage time (so-called cooling time) before reaching the energization state, and the energization time before that (so-called If the self-heating time is the same, it takes advantage of the fact that it is an almost constant time peculiar to the balance. Basically, it indicates that the warm-up is completed when the elapsed time after turning on the electric power exceeds the predetermined time. Is displayed, the energization stop time (cooling time) before the energization is measured, the energization time (self-heating time) before that is corrected, and the initial value of the elapsed time after the current energization is displayed. By setting as above, the correct display can be performed regardless of the presence or absence of power interruption for a short time.

<Examples> Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the first invention.

A first temperature sensor S ₁ is arranged in proximity to the load signal generating section 2 mainly composed of a load sensor inside the balance body 1. The first temperature sensor S ₁ also serves as a sensor for temperature compensation of sensitivity, in addition to a warming-up completion / insufficiency determination, which will be described later, and a transformer 3 and the like in the balance body 1 that constitutes a power supply circuit. Relatively far from the heat source of
In other words, the balance is placed at a position where the temperature rise due to self-heating due to energization of the balance is relatively small.

Further, the second temperature sensor S ₂ is arranged in the vicinity of the transformer 3 described above, that is, at a position where the temperature rise due to self-heating due to energization is relatively large.

The output signals of the first and second temperature sensors S ₁ and S ₂ are
After being converted into appropriate voltage values by the voltage converters 4 and 5, they are led to the load signal-temperature signal changeover switch 7 via the temperature signal changeover switch 6. The load signal from the load signal generator 2 is also guided to the load signal / temperature signal changeover switch 7. Microcomputer 8
Drives both of these changeover switches 6 and 7 to sequentially input the load signal and the temperature signals from the _first and _second temperature sensors S ₁ and S ₂ to the A / D converter 9, and the respective signals are inputted. The digital conversion data of is sampled moment by moment.

The display 10 connected to the microcomputer 8 is provided with a warming-up state display section 12 including a red lamp R, a yellow lamp Y and a blue lamp B, in addition to a digital display section 11 for displaying a measured value. There is.

The load signal generator 2 is provided in the ROM of the microcomputer 8.
In addition to the well-known weight value calculation program for compensating the load data from the first temperature sensor S1 with the temperature data from the _first temperature sensor S1 to determine the weight value and displaying it on the digital display unit 11, it is executed when the power is turned on. A warming-up state determination program whose flowchart is shown in FIG. 2 is written.

The operation and action of the present embodiment will be described below with reference to FIG. 2, but before that, the behavior of the temperature inside the main body during warm-up of a general electronic balance will be described.

When the balance is left in a power-off state for a long time, the temperature inside the balance main body 1 is substantially uniform. When the power is turned on from that state, the temperature in the vicinity of the transformer 3 which self-heats by energization rises, and the temperature in the vicinity of the load signal generating section 2 far from the transformer 3 hardly rises. If the warm-up is continued, the temperature difference between the two will gradually increase. And after the time when this temperature difference becomes more than the inherent difference due to the structure of the balance,
High-precision measurement is possible after warming up. Further, even if it is less than the above-mentioned inherent difference, in a state having a predetermined temperature difference close to this, it can be used even if it is not perfect if a predetermined small measurement error is recognized. In the present embodiment, when manufacturing the balance or the like, the above-mentioned inherent temperature difference for the warming-up completed state and the temperature difference for the usable state even if it is not perfect are obtained by experiments and the like. 8 is written in the nonvolatile memory or the like, and the respective temperature differences are, for example, 6 ° C. and 4 ° C., respectively.
It was.

Now, as shown in FIG. 2, when the power is turned on, the temperature data from the _first and _second temperature sensors S ₁ and S ₂ are taken in with the load data as described above. The difference between the temperature data from both the sensors S ₁ and S ₂ is obtained, and if the temperature difference is less than 4 ° C., the red lamp R of the warming-up state display section 12 is turned on and 4 ° C. or more
When the temperature is lower than 0 ° C, the yellow lamp Y is turned on, and when the temperature is 6 ° C or higher, the blue lamp B is turned on. As a result, the user can identify whether the warming-up is insufficient, the warming-up is insufficient, but almost usable, or the warming-up is completed depending on which lamp is lit.
When the warm-up is completed, the temperature signal changeover switch 6 is fixed to the _first temperature sensor S ₁ side, and its output is used exclusively for temperature compensation of the balance sensitivity.

It should be noted that the first and second temperature sensors S ₁ and S ₂ share one of the existing temperature sensors for other uses as in the above embodiment, or both of them share the existing one. Both can be provided exclusively for determining the warm-up state.

Further, in the above embodiment, when energization is stopped for a short period of time during energization and then re-energized, the temperature becomes almost the same as before energization is stopped, but in this case, the balance circuit is configured immediately after reenergization. Sometimes the stability of electronic components can be problematic. As a countermeasure against this, as shown in the flowchart of the main part of the warming-up state determination program in FIG. 3, the red lamp R may be unconditionally turned on for a fixed time after power-on, for example, for about 3 minutes. It is possible.

FIG. 4 is a block diagram showing the configuration of the embodiment of the second invention. In FIG. 4, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted in the following description.

In this embodiment, a timer 40 is connected to the microcomputer 8 and the timer 40 is backed up by a battery or the like.
And the elapsed time T ₂ after the energization is stopped, the elapsed time T after the energization is stored in the backup memory in the same manner, and the elapsed time after the new energization is calculated from the contents T and T _{2 of the} memory. The initial value of T is determined, and the warming-up state is determined based on the time T.

FIG. 5 shows the microcomputer 8 in this embodiment.
The operation and action of the warming-up state determination program written in the ROM will be described below with reference to this figure.

Here, in general, an electronic balance requires a substantially constant energizing time, which is peculiar to the balance structure and the like, in order to reach the warm-up completion state, and the time for reaching the warm-up completion state has not elapsed. In addition, in a state where the energization time close to this time has elapsed, it is in a usable state if a predetermined small error is recognized even if it is not perfect. In addition, momentary power failure during energization,
When the power is turned on again after the power has been stopped for a short time such as one hour, the relationship between the elapsed time after the power is turned on and the warming-up state is different. In this embodiment, the time taken to reach the warming-up state in the case where the energization stop time is long and it is not necessary to consider it, the effect of the energization stop time before reaching the energization state and the energization time before that are measured. Or based on experience, and writes it in the ROM or the like of the computer 8. Fifth
In the example shown in the figure, when the energization stop time before energization is 3 hours or more, the temperature distribution of each part of the balance becomes uniform and no influence appears. In this case, warming up is completed 1 hour or more after energization. The state is described in which it can be used even if it is not complete within 10 minutes or more and less than 1 hour.

Now, as shown in FIG. 5, the timer 40 starts time counting from the time when the power is turned on. The initial value of the time counting is the length of the measurement result T ₂ of the energization stop time before turning on the power. Depends on That is, the timer 40 is started when the power is turned off, and the elapsed time T ₂ until the power is turned on next, that is, the energization stop time T ₂ is measured. When the power supply stop time T ₂ immediately before that is 3 hours or more when the power is turned on, the initial value of the elapsed time T after the power supply is measured by the timer 40 is set to 0, but the power supply stop time T ₂ is 3 If it is less than the time, T ₂ is used to correct the previous energization time T stored in the backup memory by T = f (T ₂ ), and the corrected T is after the new energization. Is set as an initial value of a timer 40 that measures the elapsed time of. The red lamp R of the warming-up state display unit 12 is turned on when the timer 40 whose initial value has been determined in this way has the time measured for less than 10 minutes, and the yellow lamp Y for 10 or more and less than 1 hour. However, the blue lamp B is turned on again for one hour or more.

By the above determination / display operation, the actual warming-up state can be correctly displayed on the warming-up state display unit 12 even if there is a momentary power failure or the start of energization for a short time.

In the embodiment shown in FIGS. 1 and 4 above, an example in which a lamp group is separately provided for displaying the warm-up state is shown, but instead of this lamp group or together with the display by this lamp group, When the determination result of the warming-up state is not a completed state, among the weighing display values on the digital display unit 11, the digit of a digit whose blink cannot be guaranteed because of insufficient warming-up blinks,
Alternatively, it can be displayed by deleting it.

Furthermore, in each of the above embodiments, the warm-up state is displayed in three stages, but it may be displayed in two stages of a warm-up completed state and an insufficient state, or in four or more stages.

<Effects of the Invention> As described above, according to the first aspect of the invention, the balance is provided at a position near an electrical component where a temperature rise is large due to self-heating due to energization of the balance and at a position away from the electrical component. ,
The temperature is measured at least at two points, where the temperature rise due to energization is small, and when the temperature difference is within a preset difference, warming up is insufficient,
When the difference is exceeded, the warm-up completion is judged and displayed, so the temperature equilibrium inside the balance is virtually directly monitored to display the warm-up status. Regardless of the state, it is possible to always provide extremely accurate display.

Further, according to the second invention, in addition to the first time measuring means for measuring the elapsed time after the balance has been energized, the second time measuring means for measuring the duration of the non-energized state is provided,
Taking in the output of each of the time measuring means, the elapsed time after energization is corrected by the subsequent energization stop time, and the corrected elapsed time is set as the initial value of the first time measuring means at the time of re-energization after the energization stop. Since the display of the completion of warming-up is made when the time measured by the first measuring means, which is set and the initial value is set in this way, reaches or exceeds the preset time, an instantaneous power failure or a short time Even if the power is supplied again after the power supply is stopped, the accurate warming-up state can be displayed accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flowchart showing a warming-up state determination program written in the ROM of the microcomputer 8, and FIG. 3 is a warming-up in the embodiment shown in FIG. It is a flowchart which shows the principal part of the other example of a state determination program. FIG. 4 is a block diagram showing the configuration of another embodiment of the present invention, and FIG. 5 is a flow chart showing a warming-up state determination program written in the ROM of the microcomputer 8, 1 ... Balance body 2 ... Load signal Generator 3 …… Transformer 6,7 …… Changeover switch 8 …… Microcomputer 11 …… Digital display 12 …… Warming up status display 40 …… Timer

Claims (5)

[Claims] 1. A load sensor capable of outputting an electric signal corresponding to a load on a plate and an electric circuit connected to the load sensor, and the load on the plate is calculated and displayed based on the output of the load sensor. In the balance, at least two locations, one near the electrical part where the temperature rise is large due to self-heating due to the energization of the balance, and the other is far from the electrical part where the temperature rise due to the energization is small. Incorporating the temperature sensors arranged in each and the output from each temperature sensor, the warm-up is insufficient when the difference is within the preset difference, and the warm-up completion is indicated when the difference is exceeded. An electronic balance comprising: a discriminating means for discriminating the discrimination, and a display means for displaying the discrimination result. 2. The determining means, after the balance is energized,
The warming-up completion state is not determined irrespective of the output difference of each of the temperature sensors until a preset fixed time elapses. Electronic balance. 3. A load sensor capable of outputting an electric signal corresponding to the load on the plate and an electric circuit connected to the load sensor, and the load on the plate is calculated and displayed based on the output of the load sensor. In the balance, the first time measuring means for measuring the elapsed time after energizing the balance, the second time measuring means for measuring the duration of the non-energized state, and the measurement result by the first time measuring means are Discriminating means for determining whether or not the warming-up is completed depending on whether the time is longer than or equal to the set time, display means for displaying the discrimination result, and the output of each of the above-mentioned time measuring means is incorporated, and the progress after energization The present invention is characterized by including a correction unit that corrects the time with the subsequent energization stop time and sets the elapsed time after the correction as the initial value of the first time counting unit when reenergizing after the energization stop. Electronic balance to be. 4. The discriminating means discriminates between a warming-up completion state and two or more states other than the completion state, and the display means has three or more display modes according to the discrimination result. The electronic balance according to claim 1, 2, or 3, characterized in that. 5. When the determination means determines that the warming-up is not completed, the digit of the digital weighing display value of the balance that cannot be assured of accuracy due to insufficient warm-up is blinked or turned off. Claim 1 which is characterized in that
An electronic balance according to item 2, item 3, item 3, or item 4.